Activated carbon is a kind of carbon product which has high-quality anthracite, charcoal or various kinds of husks as raw materials and processed through special processes by physical or chemical methods. It has a developed pore structure and specific surface area. It has a strong adsorption capacity, so it is widely used in industrial and civil fields such as air purification, anti-virus protection, water treatment, solvent decolorization.
Although activated carbon can have many varieties in terms of appearance and use, activated carbon has a common characteristic, that is, "adsorption". The reason why activated carbon produces adsorption is because it has a developed pore structure. Like the sponge we see, under the same weight conditions, the sponge can absorb more water than other objects, because it is developed. Pore ​​Structure. However, this pore structure of activated carbon is invisible to the naked eye because they are only between 1 x 10-12 mm and 10-5 mm, which is not much larger than a molecule. The degree of development of activated carbon pores is unimaginable. If 1 gram of activated carbon is taken, all the pore walls inside will be expanded into a plane, and the area will reach 1000 square meters (the specific surface area is 1000g/m2)! The main factor depends on the degree of development of the internal pore structure.
In the production process, the only way to improve the adsorption performance of activated carbon is to control the production process, so as to increase the pore structure of activated carbon as much as possible within the unit volume. Therefore, the higher the adsorptivity of activated carbon, due to the large amount of pores, makes its own density become smaller and smaller, which is why the better the adsorption, the lighter the feel of activated carbon (provided that the same raw material is used, no dip Passing water or adsorbing other substances). At the same time, with the increase of adsorption, the production cost of activated carbon is higher, and it is a geometric progression. This is the motivation for the sale of highly adsorbed activated carbon on the market with low-adsorption activated carbon.
In order to unify the standard and control the production, in the activated carbon industry, the adsorption value of activated carbon is usually calibrated by iodine adsorption value or carbon tetrachloride adsorption value (CTC). The higher the adsorption value, the stronger the adsorption capacity of activated carbon.
With the above points in mind, it is not difficult to judge whether the performance of activated carbon is good or bad. The higher the adsorption value, the better the performance of the activated carbon. So how to easily identify the adsorption value of activated carbon without the detection equipment? Here are a few easy methods for reference.
1. Directly look at the indicators provided by the manufacturer.
The main adsorption indexes of activated carbon are: iodine adsorption value, carbon tetrachloride (CTC) adsorption value, methylene blue adsorption value, iodine adsorption value used to indicate the adsorption capacity of activated carbon for liquid substances, and carbon tetrachloride adsorption value is used to indicate The adsorption capacity of activated carbon for gaseous substances, the methylene blue adsorption value is used to indicate the decolorization ability of activated carbon. The higher the three indexes, the stronger the adsorption capacity of activated carbon. Therefore, when purchasing activated carbon, you can choose the activated carbon suitable for your own use according to your own use and the indicators provided by the manufacturer.
2, hand weight weight.
As mentioned above, in order to improve the adsorption performance of activated carbon, only the pore structure can be made on activated carbon as much as possible. The more pores, the more loose the activated carbon and the lighter the relative density, so the better the feel of activated carbon will be compared. Light, in the case of the same weight package, good performance activated carbon will be much larger than inferior activated carbon.
3. Look at the bubbles.
A small amount of activated carbon is put into the water. Due to the penetration of water, the water will gradually immerse into the pore structure of the activated carbon, forcing the air in the pores to be discharged, thereby generating a series of extremely fine bubbles, pulling out a small bubble line in the water. At the same time, it will make a sound of bubbles, which is very interesting. The more intense this phenomenon occurs, the longer the duration, the better the adsorption of activated carbon.
4, see the ability to decolorize.
Another manifestation of the adsorption capacity of activated carbon is the ability to decolorize. Activated carbon has the magical ability to turn colored liquids into light or colorless. This is actually because activated carbon adsorbs pigment molecules in colored liquids. Because of this characteristic of activated carbon, it is widely used in the production process of brown sugar to white sugar in the sugar industry. Take two transparent cups, put pure water in one cup, and then drop a drop of red ink (you can use any kind of pigment that is easy to observe but does not change the nature of the water, such as blue ink, printer color ink, However, you cannot use ink and carbon ink. After mixing, pour half of the colored water into another cup for comparison. Put the activated carbon into the colored water, the amount should reach half or more of the water, so the effect will be more obvious. After standing for 10-20 minutes, it is compared with the comparative water sample. Under the same conditions, the stronger the decolorization effect is, the adsorption of activated carbon is indicated. The better.
The following points should also be noted when purchasing activated carbon:
1. Activated carbon packaging is preferably sealed and packaged. Because the organic macromolecular substances are more or less permeated in the air, especially in the storage cabinets of the newly renovated shops or homes, the concentration of phenolic substances is extremely high, and these substances are absorbed by the activated carbon, which accumulates over time. The adsorption properties of activated carbon are reduced or even unusable due to the adsorption of these substances. Therefore, the more activated carbon with higher adsorption value, the more sealed packaging should be used to prevent the performance of activated carbon from being disturbed by the outside.
2. The counterfeit activated carbon that appears on the market now is pretending to be a semi-finished “carbonized material†of activated carbon. The carbonized material can only become a real activated carbon through the “activation†process, and the activation process is the most important pore structure in the activated carbon manufacturing process. the process of. The carbonized material that lacks this process can be said to have almost no adsorption performance, which is not harmful to consumers. Since the carbonized material is not subjected to the process of activation and pore formation, the surface is smoother than the activated carbon, and the color is white, slightly metallic, and the handle is harder than the activated carbon, and the weight is also much heavier. A considerable part of the fake activated carbon is produced by inferior raw materials, diatomaceous earth, which has extremely low carbon content, and most of them are inactive substances. The carbon color is relatively white, the hand feel is very heavy, and the particle length is long. The strength is also very high, and the collision will give a crisp sound similar to that of a ceramic tap. The hand rubs the meeting and finds that there are white fine particles on the section. When buying, you must pay attention to avoid being fooled.
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